Re: New to C# - DB question

Hi there,

Yes you are along the right track.
Firstly, you are interested in the System.Data namespace, also known as
ADO.NET
In there you will find a few sub namespaces for specific database
connections, and also some generic classes useful for all database
types.

..NET implements a disconnected architecture, where you will essentially
connect to a DB temporarily, perform some action (select, delete,
update, create), and put the results into some object, then disconnect.


There is a class called "Dataset" which can contain a collection of
"DataTable"s
A dataTable can store the result of a "select" against a database. We
generally use a "DataAdapter" to manage the SQL for us for simple table
operations (ie. a single table CRUD). A DataAdapter (such as the
System.Data.SqlClient.SqlDataAdapter) can take a DataConnection (such
as a System.Data.SqlClient.SqlConnection) object, along with some
select statement (eg Select * From sysobjects) as a string, and fill a
data table.

If you want to perform simple database statements that don't return a
whole result set, you can use the DbCommand objects (such as a
System.Data.SqlClient.SqlCommand).
The command object also takes a connection object, and a string which
is your sql statement. With the command object you have 3 methods, of
which you should concern yourself with just 2 as a beginner:
ExecuteNonQuery() and ExecuteScalar()
The former allows you to just execute some SQL, and it will return the
number of rows affected. The latter option lets you execute some sql
where you expect a single result being returned, known as a 'Scalar'.
Example of this is sql such as "Select Count(*) FROM sysobjects" which
you expect a single integer result, rather than tables with rows.

Anyways, pick which database type you are using and check out the
relative namespace. Note that you can also do quite a lot in design
mode with data adapters and datasets, and this is all very well
documented in MSDN.

Hope this helps,
Steven

.

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